Regulating transformer with contact-ring current collector



M h 1941- G. LEISCHNER 2,233,842

RING CIJRRENI' COLLECTOR REGULATING TRANSFORMER WITH coumc'r- Filld Au 13, 19:58 2 Sheets-Sheet 1 BGLeL scA-nel- $5 "A Hom March 4, 1941. LE|sHNER 2,233,842

REGULATING TRANSFORMER WITH CONTACT-RING CURRENT COLLECTOR Filed Aug. 13, 1938 I 2 Sheets-Sheet 2 Patented Mar. 4, 1941 UNITED STATES REGULATING TRANSFORMER WITH CON- TACT-RING CURRENT COLLECTOR Georg Leischner, Bonigen, near Interlaken, Switzerland Application August 13, 1938, Serial No. 224,803 In Germany August 14, 1937 '7 Claims.

The subject of the invention is a regulating transformer, that is, a regulating choking coil in which, with the aid of a deviation of the flux, the throwing in and out of winding elements or turn portions is made possible without any particular arrangement of the regulating winding. The regulating winding is the same as the low tension winding of a normal transformer and formed as a single-layer cylindrical spiral winding, with a bare outside surface serving as contact surface.

By the omission of contact paths, of connections of the same with the winding, and of tappings, an economy of more than 30 percent copper, solder for contacts and time of labour may be obtained. Also the bulk and the weight of the whole apparatus will be reduced and the reliability of service improved.

The current-collecting from the regulating winding is not done with brushes or rollers, which, together with the winding are subjected to great rear, but is effected with the aid of a contactormember shaped to make contact with the regulating winding and free to be moved along the turns of said regulating winding. Thereby the reliability of operating and the life of the arrangement, as compared with others, is greatly improved and the costs for control and maintenance are reduced. For this reason the new arrangement is especially useful as a quick-acting regulator.

Diiierent embodiments of the invention are shown in the accompanying drawings as examples.

Fig. 1 shows a longitudinal section of a regulating transformer,

Fig. 2 a cross section of the same, but without collector,

Fig. 3 and 4 show a plan and a section of a contact-ring current-collector,

Fig. 5 and 6 show a regulating transformer comprising all parts shown in Fig. 1 to 4.

Fig. '7 shows a cross section of the same regulating transformer in one position, while Fig. 8 represents another position,

Fig. 9 and 10 show a regulating transformer with two magnetic return-flux yokes,

Fig. 11 shows a regulating transformer with four magnetic return-flux yokes,

Fig. 12 shows a regulating transformer with six magnetic return-flux yokes,

Fig. 13 represents a combination of three regulating transformers to form a three-phase current-regulator,

Fig. 14 shows an arrangement analogous to that of Fig. 1.3, but having the inner return-flux yokes diiferently arranged.

Fig. 15 shows a simplified arrangement of Fig. 14.

With reference to Figs-1 and 2 the illustrated iron body comprises a core I with the magnetic return-fiux yokes 2, which are connected in parallel with a View to diminishing the dissipation of energy when the secondary winding is only partially loaded. The secondary winding is of flat copper strip wound on edge and provided with a tight intermediate insulating layer which is arranged spirally between the turns and projects beyond the outside face. The regulating transformer, thus arranged without current collector, resembles a normal power transformer.

The large circular bore 8 of the contact ring, Figs. 3 and 4, surrounds the regulating winding 4 and touches said winding at one place, while the square holes 9 of said ring encompass the magnetic return-flux yokes Z and communicate with the here by means of the slots 1 i.

By means of these slots ii the short-circuit current paths around the core 5 and the yokes 2, which the ring 5 would complete, are interrupted.

The closed portion of the ring encompasses the fluxes of core and yoke opposed to each other, so that no e1ectro-motive force is induced in the same and also no equalising or short-circuit current can be generated.

The contact making of the contact-ring current-collector 5 with the regulating winding 4 at any portion of the same is effected by spindles 6, provided in the holes Hi and running with the eccentrically arranged trunnions l in bearings 8, being rotated in synchronism, whereby the ring 5 with the inside surface of the bore 8 rolled on and along the surface of the regulating windmg.

Every time a contact surface of the ring 5 touches the winding 4 from one slot ii to the other, a half winding is thrown in.

On the passage of the contact surfaces of ring 5 at the slots H one slot at a time is overlapped by the regulating winding, so that the ring portion surrounding the hole 9 together with the portion of the winding overlapping the slot constitutes a short-circuit path of current, which, every time, encompasses a magnet return-flux yoke and dislodges the flux within the same (/2 of the main flux).

The position of the contact ring, Fig. 6, does not result in a dislodging of flux, because said ring touches the regulating winding 4 at the centre and the two slots 1 I are open.

In the position of parts represented in Fig. '7 the contact ring is short-circuited by a slot ii. The magnetic return-flux yoke 2 is encompassed and the flux in the same dislodged. The dotted line represents the path of the short-circuit current. In this position the magnetic rcturw flux yoke 2. has to carry the whole flux.

In Fig. 8 the contact ring is in the opposite position. The other slot II is now short-circuited and the flux of the return-flux yoke 2 is dislodged. The return-flux yoke 2' in this position has to carry the whole flux. The dotted line represents the path of theshort-circuit current which encompasses the return-flux yoke 2.

In the regulating transformer according to Figs. 9 and 10 two magnetic return-flux yokes (shell type transformer) are present. The regulating winding 4 is of round wire. The primary winding 3 consists of 10 branch spools, which are in parallel to diminish the leakage. The insulation between primary and secondary winding is formed as a cylindrical body, provided on its outside with a spiral groove destined to carry the regulating winding 4 of round wire. One-half of this winding l projects from the insulating cylinder and serves as a contact surface.

The contact surface of the current collector ring 5 is concave and is adjusted to the convex surface of the regulating winding 4. The current collector 5 is not circular on the outside, but is rectangular and adjusted to the profile of the transformer. The spindles 6 with trunnions or eccentrics "i are arranged outside on both sides of the magnetic return-Jinx yokcs.

The spindles 5 are threaded, the pitch of which corresponds to that of the regulating winding 4. The spindles 6 are connected by pinicns (which could also be chain or crank gears) in such a manner with each other, that, on a synchronous running of the same, a correct guiding of the contact ring along the regulating winding is ensured.

Should a safe guiding or displacing oi the contact ring 5 be effected by the concave or convex or otherwise profiled arrangement of the regulating winding and contact ring and by the insulating spiral projecting between the turns of the regulating winding, then, in place of the spindles smooth shafts provided with eccentric trunnions could be used, the contact ring being displaced on the surface of said shafts. To obtain a better guiding of this ring and to avoid a tipping over or a jamming between it and the spindles it is advisable to provide the holes I 0 (Fig. 3) with annular borders or ledges.

In order to get a smooth contact pressure between current collector and regulating winding and to fit the contact ring to the unevenness of the regulating winding. it is advisable to provide resilient bearings for the trunnions of the spindles 6. Then it will also be possible to operate with a great number of revolutions of the spin dles and to use the regulating transformer as a quick-acting regulator.

The embodiments of regulating transformers, Figs. 1 to 10, described in the above, are formed with two magnetic return-flux yokes, whereby one throwing-in and cutting out of half-turns of the regulating Winding only is possible.

But if the throwing-in and regulating steps should be smaller than one-ha1f turn (fine-regulator), the number of the magnetic return-flux yolzes must be increased. This is the case in the regulating transformer according to Fig. 11, which comprises four magnetic return-flux yokes 2 and a contact ring 5 with four contact seg ments. This contact ring is driven by the spindles or shafts 6 and is rolled along the surface of the contact Winding 4. The primary winding 3 is located inside the regulating winding 4 and encompasses the cores I which carry the flux. Each magnetic return-flux yoke carries the flux 4 /4.

At the passing of the contact ring 5 from one segment to the other a quarter of the flux is dislodged. The throwing in and cutting out. of the regulating winding is made with quarter turns.

Fig. 12 shows a regulating transformer with a. core I and six magnetic return-flux yokes 2 each of which carries I /6 of the main flux 1' The primary winding 3 is arranged inside, while the regulating winding 4 is arranged outside. The contact ring 5, driven by the shafts or spindles 6, is provided with six contact segments rolling along the smooth surface of the regulating winding during the regulating operation.

During the regulating process one sixth of a turn at a time is thrown in or cut out.

By increasing the number of the magnetic rcturn-flux yokes and contact segments of the contact ring, the fne-regulation may be improved at will.

A combination of three regulating transformers, forming a. three phase regulator, is represented in Fig. 13. The cores I carry the primary winding 3 on the inside, while the secondary winding 4 is arranged on the outside. Each core I has two magnetic return-flux yokes 2, 2' arranged on both sides of the same. The contact rings of the three transformers are combined in one segment 5, which is driven by the spindles or shafts 6 journalled by means of the trunnions l and is moved along the regulating winding 4. Each of the slots between the halves of the contact surfaces is staggered at 120 in the different transformers. Thereby the dislodging of the flux of the single transformers, that is, of the return- I'illX yok-es, is effected alternately with spacings of 60 angular movement of the contact segment.

Fig. 14 shows an arrangement analogous to that of Fig. 13 with the difference, that the return-flux yokes 2 on the inside are each united to form one return flux yoke, carrying the fluxes of two neighbouring phases. The marking of parts in Fig. 14 is similar to that in Fig. 13.

The arrangement represent-ed in Fig. 15 is simplified compared to that of Fig. 14. By the omisslon of the magnetic return-flux yokes 2 (Fig. la) the apparatus is changed into a five-legged transformer with three main cores I and two return fiux-yokes 2 arranged on the two sides.

These return-flux yokes 2 receive alternately the dislodged flux during the throwing-in operation. The spindles 6 with the trunnions 1 drive the contact segment.

For a better and a safer contact making the contact segment 5 (Figs. 13 to 15) forming a whole, may be formed with three single segments provided with flexible electrically conducting intermediate members and may carry resilient connections to transmit the adjusting forces, so that the segments of the single phase windings may be adapted individually to the occasional condition of the regulating winding.

Since the contact segments 5 in the regulating transformers according to Figs. 13 to 15 form the neutral point of the regulating winding, the electric separation may be eifected in three partial segments with insulating pieces, also in such cases where an electric division of the single phases is necessary.

The leading away of the current from the contact segments is effected by means of flexible connections or slide rails.

Also the spindles or shafts B may be used as conductors from the movable contact system to the stationary terminals. In all embodiments, also oval or rectangular windings with contact segments fitted to the surface form of the same, maybe used instead of the circular Winding.

The regulating windings may also be made of aasacac aluminium with a thin coating of copper (Cupal).

The small webs 52 of the contact segments 5 (Fig. 3) may be fo med with an increased resistance or as resistance connectio is to damp the short-circuit current during the disconnection of the flux or to reduce it to harmlessness. The current admission is effected preferably ,at the middle portion of the resistance connections, so that one-half of the current flows to each side; since all centres of these resistance connections carry the same potential, they may be connected to each other metallically thus forming one conneotion.

The surface of the regulating winding may also be provided with grooves or flutings into which the contact ring engages to ensure a safer contact-making and guiding.

Also the outer edge of the regulatin winding may be made flat and projecting and with lateral contact surfaces, which are in contact with flange-like edges of the contact ring to ensure a safe contact.

The surface of the regulating winding of the inside surface of the contact ring may be provided with projecting portions similar to pressure contacts which serve as good contact makers.

A regulating transformer according to the invention may be used with advantage as chokecoil to commute the load current in step transformers from one step to the other.

The apparatus is also especially adapted as an adjustable inductance for electric welding and for many other purposes.

The regulating transformers may also be constructed with several current collectors for each regulating winding. For regulating transformers of powerful currents several electrically separated windings may be arranged inside one another or, if consisting of several groups, one above the other, each of said groups being provided with one or more current collectors.

In order to obtain great variations of voltage with a small number of revolutions of the driving spindles or shafts it is advisable to arrange two or more transformers above or alongside each other and to connect their current collectors electrically with each other in such .a way that these, serving as transmitting bridges, connect the additional turns of the regulating windings or groups of the regulating windings of the transformers in series, so that the regulated voltages may be collected from the winding ends. With the aid of these arrangements, for instance, any number of winding groups of two or more transformers may be connected in series with several collector groups.

When several current collectors are used in a transformer or in a group of transformers, linked to each other, it is advisable to arrange the movement of the current collectors so that, at the same time, only one of these is in the short-circuit position and thereby, at the same time, one branch flux only of the respective transformer or transformer group flowing over the returnfiux yokes can be dislodged. Thereby the shortcircuit current and the short-circuit output is, in a transition position, considerably reduced, whereby also the non-load current and the nonload output is lessened.

What I claim as new is:

l. A regulating transformer comprising a magnetic circuit with a plurality of flux return path cores, primary and secondary windings interlinked with said cores, the secondary winding being a circular coil and serving as a regulating Winding, a contactor plate surrounding the regulating winding and having a circular opening of greater internal diameter than the external diameter of said regulating winding and making a one point electrical contact with said winding, said contactor plate having slots therein traversed by the said cores, the walls of each slot adjacent the internal circumference of the opening having a gap therein capable of being bridged by the external rim of said regulating winding, and means for shifting the point of contact between said contactor plate and said regulating winding in a circular path to bridge any of said slot gaps and for shifting said point of contact axially to bring any desired turn of said regulating winding into contact with said contactor plate.

A regulating transformer according to claim 1, in which the turns of the secondary winding are spaced from each other by an interval not exceeding the diameter of the wire of said secondary winding.

A regulating transformer according to claim 1, in which the portion of the contactor plate between its outer circumference and the adjacent side of each slot forms a high resistance element in said contactor plate.

1-. A regulating transformer according to claim 1, in which the shifting means includes a pair of diametrically spaced spindles and in which each spindle is provided with an eccentric for shifting the contactor plate.

5. A multi-phase transformer comprising three magnetic circuits each with a plurality of flux return path cores, primary and secondary windings for each magnetic circuit and each interlinked with said respective cores, each secondary winding being a circular coil and serving as a regulating winding, 2. contactor plate surrounding the regulating windings and having three circular openings each of greater internal diameter than the external diameter of said regulating winding and making a one point electrical contact with said winding, said contactor plate having slots therein for each opening traversed by the said cores, the walls of each slot adjacent the internal circumference of the opening having a gap therein capable of being bridged by the external rim of said regulating winding, and means for shifting the three points of contact between the contactor plate and the regulating windings in circular paths to bridge any of said slot gaps and for shifting the points of contact axially to bring any desired turn of said regulating windings into contact with the contactor plate.

6. A regulating transformer according to claim 1, in which a plurality of cores are provided, and in which the contactor plate is provided with a pair of slots for each core.

7. A regulating transformer according to claim 1, in which ohmic resistances are provided in the contactor plate of which the resistances connect the parts of the plate lying on both sides of each opening.

GEORG LEISCHNER. 

